On Tuesday, a judge in West Virginia sentenced Hughart to 42 months in jail and three years of supervised release.

Hughart, 54, of Crab Orchard, W. Va., is also "the highest-ranking mine official ever convicted of conspiracy to impede MSHA [the Mine Safety and Health Administration] or conspiracy to violate mine health and safety standards," says Booth Goodwin, the U.S. Attorney for the Southern District of West Virginia.

Hughart had no direct involvement in the operation of Massey's Upper Big Branch mine, where 29 coal miners died in a massive explosion in April, 2010.

But he was a Massey manager and executive for more than 20 years, serving as the senior official at subsidiary companies which controlled other coal mines. He is helping prosecutors gather information about the corporate culture at the company, which investigators blamed for the Upper Big Branch tragedy.

In a plea agreement, Hughart admitted to being part of a corporate conspiracy to evade surprise mine safety inspections by giving advance warning to miners underground.

Many coal mines are so big and so deep that even surprise arrivals by federal mine inspectors give mine managers time to warn workers. They can then fix obvious safety violations before inspectors reach them.

In an earlier court hearing, U.S. District Judge Irene Berger asked Hughart to identify the participants in the conspiracy. "The CEO," he responded, in reference to former chief executive Don Blankenship, who denies any wrongdoing and has not been charged.

Goodwin has indicated that he's aiming higher up the corporate ladder at Massey Energy as his criminal probe continues. Massey was absorbed by Alpha Natural Resources in 2011 but some former Massey executives, including those involved in the management of some of Massey's most troubled mines, continue in senior positions at Alpha.

The sentence of 42 months exceeds by a year the top end of federal sentencing guidelines for the crime, according to Goodwin. Earlier Tuesday, Hughart's bail was revoked for his arrest last month on drug charges. But Judge Berger indicated that the additional time is due to the severity of the mine safety violation and not the drug arrest.